In a multiyear investigation of New York City’s Rikers Island correctional facilities, the Justice Department found that teenage inmates were frequently subjected to brute force and other violations of their constitutional rights.

The federal probe, focused on the period from 2011 to 2013, described a “deep seated culture of violence” at the adolescent facilities at Rikers, Aljazeera America reports. Corrections department staff routinely used force “not as a last resort but instead as a means to control the adolescent population and punish disorderly or disrespectful behavior.” Beatings frequently occurred in areas where there were no security cameras, The New York Times notes.

Preet Bharara, U.S. attorney for the Southern District of New York, who released the report on Monday, characterized Rikers Island as “a broken institution,” according to Aljazeera America. “It is a place where brute force is the first impulse rather than the last resort, where verbal insults are repaid with physical injuries, where beatings are routine while accountability is rare and where a culture of violence endures even while a code of silence prevails.” Nearly 44 percent of the adolescent male population in custody as of October 2012 had been subjected to force by the correctional staff, the Times reports.

In 2012, 517 incidents of use of force by staff resulted in 1,059 injuries; in 2013, 565 instances of force resulted in 1,057 injuries. The figures are high, the report said, considering that the average daily adolescent population at Rikers was only 682 in 2013 and 791 in 2012, Aljazeera America reports. Correction officers frequently resort to “headshots” – blows to an inmate’s head or face, investigators found. The DOJ identified 64 incidents of blows to an adolescent inmate’s head or face. “Punitive segregation” (solitary confinement), was used as a disciplinary measure.

New York Mayor Bill de Blasio has promised reforms for Rikers Island. Joseph Ponte, the new commissioner of the DOC, promises system wide initiatives to make jails safer, including more security cameras in Rikers. The report calls for adolescents to be removed from Rikers Island entirely.